KR102406086B1 - Sealing system, method and watercraft - Google Patents

Abstract

A sealing system is disclosed for sealing a shaft located under water, in particular a propeller shaft of a ship, comprising two sealing systems, preferably the sealing system remote from the propeller comprises at least one lip for separating the air chamber from the lubricant chamber. A sealing system having a seal and adjacent a propeller has a machine room seal, wherein the air pressure in the air chamber is greater than the lubricating oil pressure in the lubricant chamber, and a method of sealing a shaft, in particular a propeller shaft, is disclosed.

Description

SEALING SYSTEM, METHOD AND WATERCRAFT

The present invention relates to a vessel comprising a sealing system for sealing a shaft located under water according to the preamble of claim 1 , a method for sealing a shaft located under water and a sealing system for sealing a propeller shaft.

A conventional sealing system for sealing a propeller shaft in a ship has a bush that can be positioned on the shaft and connectable to the shaft for rotation together, the bush being surrounded by a housing secured to the bush. At least one lubricant chamber open to the bush and one air chamber open to the bush are formed in the housing. The chambers are sealed to each other via a seal ring. Also provided is a mechanical seal adjacent a propeller comprising a bush. Through the supply line and the discharge line a continuous air stream is conducted through the air chamber and thus through the annular chamber. The lubricant chamber is associated with continuous grease lubrication of the at least one seal ring.
According to US2014048461 (A1), at least one oil-filled seal chamber bounded by a seal ring around the shaft, as well as an oil storage tank, an oil supply line connecting the tank to the bottom part of the seal chamber, the tank and the seal A sealing arrangement for a propeller shaft of a ship is known, comprising an oil circulation pump interposed in a supply line between the chambers, and an oil return line in reverse communication from the top of the seal chamber to the tank.
However, grease lubrication has the disadvantage of clogging the air line when grease enters the air chamber, requiring regular rinsing in an expensive manner. Furthermore, grease is not an optimal lubricant and coolant for seal rings preferably composed of elastomers, as a result of which grease lubrication adversely affects service life and in particular loadability. The continuous airflow also releases salts and minerals that may reach the air chamber when water enters, possibly clogging the air line.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sealing system for sealing a shaft located under water, which obviates the above-mentioned disadvantages and which in particular enables a reliable, low-maintenance and highly loadable shaft seal. will do It is also an object of the present invention to provide a method for sealing a shaft located under water as well as a ship comprising a propeller shaft sealed in this way.

This object is achieved by a seal system comprising the features of claim 1 , a method comprising the features of claim 8 and a ship comprising the features of claim 10 .

A sealing system according to the invention for sealing a shaft located under water comprises a bush disposed on the shaft and connectable to the shaft for rotation together, the bush surrounded by a housing fixed to the bush. At least one lubricant chamber open to the bush and one air chamber open to the bush are formed in the housing. The chambers are sealed to each other or axially separated from each other via a seal ring. For this purpose, a mechanical seal adjacent to the propeller surrounding the bush is provided. The sealing system includes at least one supply line and one exhaust line for supplying air into the air chamber and exhausting the air out of the air chamber. According to the present invention, lubricating oil in fluid communication with the lubricant tank via at least one oil line is filled in the at least one lubricant chamber, wherein the air pressure in the air chamber is greater than the oil pressure in the lubricant chamber.

Because the internal chamber pressure of the air chamber is higher than that of the lubricant chamber, it is prevented that lubricant oil from the lubricant chamber can enter the air chamber. If there is not enough air pressure, the oil pressure raises the seal ring. Thus, oil ingress is prevented. The oil pressure in the lubricant chamber is preferably greater than the reference pressure by 0.02 bar to 0.2 bar at the reference level. The oil pressure can be set, for example, by placing the lubricant tank higher than the reference level when viewed in the vertical direction. The air pressure or resting air pressure in the air chamber is preferably greater than the oil pressure by 0.1 to 0.5 bar. The reference level is located at the height of the shaft axis of rotation or the longitudinal axis of the shaft and therefore has a height of exactly zero relative to the reference level. If lubricating oil unexpectedly enters the air chamber, it is nevertheless not possible to block the air line and in particular the exhaust line due to the high fluidity, thus ensuring air supply of the air chamber and in particular air and leak-discharge from the air chamber even when lubricating oil enters. . In addition, the lubricating oil has a better lubricating and cooling effect on the seal ring preferably made of an elastomer than a lubricating grease commonly used. The sealing system of the invention is particularly suitable for sealing propeller shafts on ships with or without pod drives. The bush here can be, for example, a so-called shaft protection bush that prevents direct contact of the propeller shaft with seawater and is connected to the propeller. With only the oil line, cleaning of the at least one lubricant chamber can be done through the air chamber; That is, the oil pressure is increased so that lubricating oil enters the air chamber from the lubricant chamber and discharges therefrom through the discharge line. Only one oil line is preferably arranged above the lubricant chamber in the installation position of the shaft. If an additional oil line is provided, an oil circuit or continuous oil supply can be realized by means of the lubricant chamber, the oil supply and oil extraction preferably taking place in the opposite manner. However, since the second oil line may also be controlled to drain the lubricant chamber, a discontinuous oil supply occurs despite the two oil lines. Of course, additional oil lines may also be provided, such as, for example, two supply-side oil lines and one discharge-side oil line.

The sealing system preferably has a control device acting on the supply side compressed air control valve and/or the discharge side valve arrangement. For example, the air-electric control device enables automatic drainage of the air chamber after a predetermined time interval. Preferably, therefore, no continuous air stream is guided through the air chamber, but rather a discontinuous air conduction occurs, which is expressed in terms of reduced air consumption compared to the prior art described above. Drainage or blowing itself is achieved via an increase in air pressure and is preferably regulated via a control device. For this purpose it may act on an air pressure regulating valve which accordingly controls the fluid connection to the compressed air source or to the on-board compressed air network. In order to ensure a pressing-out of liquids that are likely to collect in the air chamber, for example due to unexpected water ingress and/or oil ingress, the outlet air pressure is, for example, 0.2 to 0.5 relative to the drain height. can be increased by bar.

Alternatively or in addition to the control device, a liquid measuring device can be arranged on the supply side by which the liquid or moisture content in the line can be determined. The liquid measuring device is embodied to generate an alarm signal at a predetermined liquid or moisture level to indicate the need for a draining process and/or to transmit an activation signal to the control device, so that the draining process is automatically initiated via the control device as a result. can be This ensures that the draining of the air chamber is carried out even if the predetermined time interval of the control device has not yet expired or has been reached. This is especially the case for unexpected events such as water and/or oil intrusions.

A collection container for collecting the liquid discharged from the air chamber and a fill level meter may be disposed on the discharge side of the air chamber, and when a maximum liquid level in the container is reached, the fill level sensor is a control device to initiate a draining process sends an activation signal and/or triggers an alarm signal. The collection vessel comprising the fill level sensor can alternatively or additionally be arranged on the supply line side of the liquid measuring device. If a collection container comprising a liquid meter is alternatively provided on the supply line side of the liquid metering device, it is possible to prevent that the drainage treatment of the air chamber is performed when a predetermined time interval of the control device has not yet expired or has not been reached. guarantee This is especially the case for unexpected events such as water and/or oil intrusions. If the collection container is additionally provided with a liquid meter, the liquid is guided in a targeted manner from the air-side discharge line and overflow of the collection container is prevented by the liquid meter.

In order to prevent an uncontrolled drop in air pressure in the air chamber during drainage of the air chamber, a throttle or throttle line may be provided on the outlet side. If the valve arrangement described above is provided, the throttle is located downstream of the valve arrangement or between the valve arrangement and the outlet.

Preferably the at least one lubricant chamber is sealed on the side opposite the air chamber with respect to the interior, wherein an internal pressure lower than the oil pressure is present on the basis of a reference level. The higher oil pressure relative to the internal pressure prevents air from penetrating from the inside into the lubricant chamber through the seal disposed between the lubricant chamber and the interior. If there is not enough oil pressure, the seal ring is lifted by air pressure. When a sealing system is incorporated into a vessel's pod drive, it is good when atmospheric pressure or environmental pressure outside the vessel above the waterline is present inside or inside the pod. Therefore, atmospheric pressure at the water level exists inside.

Preferably, the air chamber is in fluid communication with the annular chamber of the mechanical seal, the annular chamber being open to or delimited by the bush. The annular chamber is therefore also affected by the air pressure. Thereby, it prevents or at least prevents the penetration of seawater into the annular chamber, for example in case of a failure of the mechanical seal. In addition, the annular chamber is also drained by blowing in the air chamber.

In the method of the present invention for sealing a shaft located under water, at least one lubricant chamber open to the shaft is filled with lubricant, an axially adjacent air chamber open to the shaft is filled with air, and the chamber is radially closed by the shaft or by a bush disposed on the shaft inwardly in the direction, a seal ring is disposed between the chambers, the seal ring separating the two chambers from each other, according to the invention the air pressure in the air chamber is set to be greater than the oil pressure in the lubricating oil chamber. The method of the present invention enables a reliable and low-maintenance sealing of the propeller shaft of a ship.

If the air chamber is drained intermittently, air consumption can be kept low. Due to the intermittent drainage, an air flow is formed only during the drainage process, but the air chamber is sometimes opened in the direction of the discharge line.

The vessel of the present invention is provided with the sealing system of the present invention for sealing at least one propeller shaft. Accordingly, a vessel with a reliable, low maintenance, low energy propeller shaft side seal is provided.

Other advantageous exemplary embodiments of the invention fall within the subject matter of other dependent claims.

In the following two preferred exemplary embodiments of the invention are described in more detail with reference to the schematic drawings.
1 shows a schematic structure of a first exemplary embodiment of a sealing system according to the invention;
2 shows a second exemplary embodiment of a sealing system according to the invention.

1 shows a first embodiment of the sealing system 1 of the invention of a shaft 2 located under water. The shaft 2 is rotatable about a longitudinal axis 3 and is preferably a propeller shaft of a ship. As can be seen, in the installed position and the floating position of the vessel, it is oriented essentially horizontally or at a slight angle to the horizontal. The longitudinal axis 3 or the shaft rotation axis provides reference levels for the refill level h1, the drain height h2 and the measurement height h3, which are described in more detail below. The shaft axis of rotation 3 is substantially at a reference level at height h0.

Here, the vessel has at least one driving-side pod 4 suspended pivotably in the vertical direction on the hull 6 of the vessel. The shaft 2 is guided through an opening 8 from the interior 10 of the pod 4 into the seawater space 12 and is provided with a propeller 14 on the end side.

The sealing system 1 essentially has a shaft seal 16 as described below, a lubricant supply as described below and an air supply as described below.

The shaft seal 16 includes at least one bush 18 disposed on the shaft 2 , which has an annular flange 20 that allows them to rotate together and screw onto the propeller 14 . The bush 18 is surrounded by a housing 22 having a ring flange 24 for attachment to a pod section 26 surrounding the opening 8 . Thus, the bush or shaft protection bush 18 surrounds the shaft 2 over its entire free length outside the pod and protects it from seawater.

The housing 22 defines an air chamber 28 open to the bush 18 and a lubricant chamber 30 axially adjacent to the bush 18 and also open. Here the lubricant chamber 30 is located on the side of the air chamber 28 facing the pod 4 . Chambers 28 , 30 are formed in housing segments 32 , 34 respectively and are sealed to each other by seal rings 36 . The seal ring 36 is a radial shaft seal ring, in particular here an elastomeric lip seal oriented towards the air chamber 28 . To seal the annular gap 38 formed between the bush 18 and the housing segment 40 forming the annular flange 24 , the housing segment ( A seal ring 42 is inserted between 34 and the housing segment 40 . The seal ring 42 is also a radial shaft seal ring, in particular an elastomeric lip seal oriented towards the lubricant chamber 30 . By orienting the seal ring or lip seal 36 within the air chamber 28 and orienting the seal ring or lip seal 42 within the lubricant chamber 30, each seal lip is typically formed in a high pressure fillable chamber 28, 30) protrude inward.

A mechanical seal 44 is provided between the air chamber 28 and the ring flange 20 of the bush 18 receiving the propeller 14 . The mechanical seal 44 has a slide ring 46 disposed on a bush 18 , the slide ring 46 having a propeller side clamp ring 48 located on the bush 18 and a bearing housing side counter It is disposed between the rings 50 . The rotating slide ring 46 is in preloaded contact with a non-rotating counter ring 50 which is inserted into an unmetered axial recess of the housing segment 32 forming the air chamber 28 . In order to prevent the entry of water on the outer peripheral side of the counter ring 50 into the air chamber 28 , an outer seal ring 52 is inserted between the counter ring 50 and the opposite inner peripheral section of the axial recess. A seal bellows 54 , for example an elastomeric seal bellows, is disposed on one side of the slide ring 46 facing the clamp ring 48 . The seal bellows 54 has a vulcanized slide ring receptacle 55 clamped at one end by a clamp ring 48 and operatively connected through a non-quantitative attachment with a slide ring 56 at its other end. include Mechanical seal 44 defines an annular chamber 56 surrounding bush 18 , which is in fluid communication with air chamber 28 through an annular gap 58 .

The air supply functions to supply air to or exhaust air from the air chamber 28 . For this purpose at least one supply line 60 opening into the air chamber 28 and one outlet line 62 extending from the air chamber 28 , a compressed air source 64 , and a solenoid valve 66 . A valve device such as In the exemplary embodiment shown here, the supply line 60 is disposed above the discharge line 62 , so that liquid can be reliably drawn from the air chamber 28 . The supply line 60 is preferably connected to a compressed air source 64 , which is preferably arranged in the hull 6 of the ship and thus above the pod 4 with respect to the axis of rotation 3 in the installation position. are placed The compressed air source 64 here represents the ship-side compressed air network into which the air supply is incorporated. Of course, instead of incorporation into the ship-side compressed air network, a separate compressed air source 64 may also be provided only for the sealing system 1 or its air supply. A valve arrangement 66 for opening and closing the discharge line 62 is arranged on the discharge line side and here in the hull 6 of the vessel. The exhausted air can be supplied via a valve arrangement 66 to a collection container 68 , for example of a bilge 68 . In order to avoid uncontrolled air pressure drop in the air chamber 28 during blowing, a throttle or throttle line is provided downstream of the valve arrangement 66 or between the valve arrangement 66 and the bilge 68 . The discharge line section 71 downstream of the valve arrangement, and here the discharge line section receiving the throttle 70, is located at a drain height h3 based on a reference level, the drain height h3 representing the highest point of the discharge line. .

A control device 72 is also arranged on the supply line side of the air chamber 28 , the control device 72 acting on the valve device 66 via the control line 74 . After a certain time interval, the control device 72 performs automatic draining or blowing of the air chamber 28 . For this purpose, the control device 72 provides a corresponding opening signal to the valve device 66 via the control line 74 . The control device 72 simultaneously controls the flow cross-section of the supply line-side pressure regulating valve 75 disposed downstream of the compressed air source 64 so that a continuous air flow is guided through the air chamber 28, and further, The exhaust air pressure increases relative to the remaining air pressure. The pressure regulating valve 75 is preferably a proportional pressure regulating valve. A liquid measuring device is arranged downstream of the control device 72 and thus between the control device 72 and the air chamber 28 , using said liquid measuring device 76 for example water into the air chamber 28 . Alternatively, the liquid or moisture content in the supply line 60 may be determined due to lubricating oil intrusion. Via signal line 78 the liquid measuring device 76 provides an activation signal to the control device 72 . Alternatively or additionally, it is possible to trigger an alarm signal. It is preferably located at the drainage height h3 with respect to the reference level. During the blowing of the air chamber 28 the discharge pressure is increased by 0.2 to 0.5 bar for a corresponding water column of drain height h3.

The lubricant supply unit serves to supply and discharge lubricant into the lubricant chamber 30 to lubricate the seal rings 36 and 42 . For this purpose at least one lubricant tank 80 , one supply line 82 opening into the lubricant chamber 30 , and one discharge line extending from the lubricant chamber 30 , and a lubricant pump 86 are provided. provided The provision of the two oil lines 82 , 84 is merely exemplary here. Of course only one oil line 82 or two or more oil lines 82 , 84 are also conceivable. The supply line 82 and the discharge line 84 are in fluid connection with the lubricant tank 80 so that circulating pumping of the lubricant can be achieved or a continuous lubricant can be guided through the lubricant chamber 30 . In the exemplary embodiment shown here comprising two oil lines 80 , 82 , in particular the supply line 82 is arranged below a reference level so that the gas in the lubricant chamber 30 can be reliably drawn out and A discharge line 84 is disposed above the reference line. Here, the lubricating oil discharged from the lubricant chamber 30 may be subjected to a cleaning process not described further, such as possible dehydration, degassing and desalination, and may be supplied back to the lubricant chamber 30 as fresh oil. The lubricant tank 80 is preferably located in the interior 10 of the pod at a refill height h1 relative to a reference level. With respect to the measuring height h1 and the draining height h3, the lubricant tank 80 is vertically oriented between the air supply and supply line side liquid measuring device 76 and the air supply and discharge line side discharge line section 71 . is placed as The lubricant tank 30 is arranged such that, in particular at the height of the reference level, the oil pressure increased by about 0.02 bar to 0.2 bar relative to the reference pressure or internal pressure prevails in the lubricant chamber 30 .

The lubricant pump 86 is used to empty or fill the lubricant tank. In the exemplary embodiment shown here, the lubricant pump 86 is located on the hull side of the vessel and is therefore not disposed on the pod 4 .

To measure the lubricant level in the lubricant tank 80 , a fill level meter 88 is disposed therein. It is implemented in a simple form as a float switch and is operatively connected to a lubricant pump 86 for automatic refilling when the minimum lubricant level falls below. The lubricant tank 80 is vented through a ventilation line 90 which is openable through a shut-off valve 92 . The shut-off valve 92 is preferably electrically operable and closes upon damage to the seal ring 36 .

In the following the preferred method of the invention for sealing the shaft 2 located under water is described in more detail. In operation, a continuous flow of oil is guided through the lubricant chamber 30 using a lubricant supply to oil the seal rings 36 and 42 . The oil pressure in the lubricant chamber 30 arising from the refill height h1 is preferably set. In the exemplary embodiment described herein, the oil pressure is 0.02 to 0.2 bar higher than the internal pressure of the interior 10 of the pod 4 at the height of the reference level. It is preferred that atmospheric pressure prevails in the interior 10 .

The air chamber 28 is filled with a resting air pressure using a control device 72 and a pressure regulating valve 75 , which is 0.1 to 0.5 bar higher than the oil pressure in the lubricant chamber 30 . high. In normal operation, the exhaust line 62 of the air chamber 28 is closed. During the drain operation, ie after a time interval recorded by the control device 72 , the draining process of the air chamber 28 is initiated. For this purpose, the pressure regulating valve 75 is opened via the control device 72 , and the air pressure in the air chamber 28 corresponds to a so-called water column at the drain height h2, for example between 0.2 bar and 0.5 bar. increased by bar, pushing the currently present liquid out of the air chamber 28 . At the same time the valve device 66 is actuated via the control device 72 by means of an open signal, so that the discharge line 62 is opened towards the bilge 68 .

After the occurrence of blowing or draining, the valve device is actuated via the control device 72 by means of a closing signal, and thus the discharge line 62 is closed. At the same time, the air pressure is set to the reduced pressure value via the pressure regulating valve 75 . The resting air pressure is then automatically held constant via the pressure regulating valve 75 .

If the liquid measuring device 76 records a predetermined liquid or moisture content in the supply line 60 at the measuring height h3, preferably the liquid measuring device 76 sends the signal line 78 irrespective of the time interval being reached. provides an activation signal to initiate the draining process to the control device 72 via Accordingly, the liquid measuring device 76 represents an additional device in the control device 72 so that a timely or immediate drain of the air chamber 28 is ensured even in case of sudden water and/or oil intrusion into the air chamber 28 . In addition, drainage of the air chamber 28 is ensured using the liquid device 76 even if the timing of the control device 72 unexpectedly malfunctions. However, the draining may also be performed manually by an operator. For this purpose, the liquid measuring device 76 may trigger an alarm signal. However, an alarm signal can also be generated with an automatic draining device to alert operating personnel of liquid intrusion to perform corresponding actions, such as monitoring and/or repair actions.

Since the seal ring 36 is oriented towards the air chamber 28 between the air chamber 28 and the lubricant chamber 30 , it is always pressed against the bush 28 via air pressure and consequently the lubricant chamber 30 . Elevation of this seal ring 36 by the lubricating oil located in ) is prevented. Similarly, the seal ring 42 between the lubricant chamber 30 and the interior 10 of the pod 4 is pressurized by the lubricating oil against the bush 18 so that the internal pressure from the bush 18 to the seal ring 42 ) is prevented from rising.

Unlike the first exemplary embodiment according to FIG. 1 , in the exemplary embodiment shown in FIG. 2 of a seal system 1 according to the invention, in the air chamber 28 as an additional device to the control device 72 . Instead of the liquid measuring device 76 on the supply side, an additional device is arranged on the outlet line side of the air chamber 28 . It has a collection container 94 and a fill level meter 96 for collecting the liquid discharged from the air chamber 28 . Liquid from the air chamber 28 passes into a collection container 94 and accumulates there. The charge level meter 96 is connected to the control device via a signal line 78 . When a predetermined liquid level in the collection container 94 is reached, the fill level meter 96 provides an activation signal to the control device 72 via a signal line 78 , the control device 72 is illustrated in FIG. 1 . Initiate the draining process.

Also, in particular during the draining process controlled by the control element 72 , the collection container 94 serves as a collection point for the discharge of liquid from the discharge line 62 to the adjacent air chamber. The liquid composition and/or the amount of liquid collected in the collection container 94 here provides information about the sealing effect of the seal rings 36 , 42 . Here, based on the liquid amount and/or liquid composition, the control device 72 can itself set or readjust the time interval for regular automatic draining of the air chamber 28 , and also the sealing ring 36, 42), a predetermined time point is defined.

A sealing system is disclosed for sealing a shaft located under water, in particular a propeller shaft of a ship, comprising two sealing systems, preferably the sealing system remote from the propeller comprises at least one lip for separating the air chamber from the lubricant chamber. A sealing system having a seal and adjacent a propeller has a machine room seal, wherein the air pressure in the air chamber is greater than the lubricating oil pressure in the lubricant chamber, and a method of sealing a shaft, in particular a propeller shaft, is disclosed.

1: sealing system
2: shaft / propeller shaft
3: longitudinal axis / shaft rotation axis / reference level
4: Ford
6: Ship hull
8: opening
10: inside
12: sea water space
14: propeller
16: shaft seal
18: bush / shaft protection bush
20: annular flange
22: housing
24: annular flange
26: pod section
28: air chamber
30: lubricant chamber
32: housing segment
34: housing segment
36: seal ring / lip seal
38: ring gap
40: housing segment
42: seal ring / lip seal
44: mechanical seal
46: slide ring
48: clamp ring
50: counter ring
52: outer seal ring
54: seal bellows
55: slide ring receptacle
56: annular chamber
58: annular gap
60: supply line
62: release line
64: compressed air source
66: valve device
68: collection container / bilge
70: throttle / throttle line
71: discharge line section
72: control device
74: control line
75: pressure regulating valve
76: liquid measuring device
78: signal line
80: lubricant tank
82: supply line
84: discharge line
86: lubricant pump
88: fill level meter
90: ventilation line
92: shut-off valve
94: collection container
96: fill level meter

Claims (10)

a bush (18) displaceable on the shaft (2) and connectable to the shaft (2) for rotation therewith, the bush (18) being surrounded by a housing (22) fixed with respect to the bush (18), At least one lubricant chamber 30 open to the bush 18 and an air chamber 28 open to the bush 18 are formed in the housing 22 , the chambers 28 and 30 having a seal ring 36 . a supply line (60) and an exhaust line (18) sealed to each other via
Lubricating oil in fluid communication with the lubricant tank 80 through one or more oil lines 82 , 84 is charged to the one or more lubricant chambers 30 , wherein the air pressure in the air chamber 28 is higher than the oil pressure in the lubricant chamber 30 . A sealing system (1) for sealing a larger, sub-water shaft (2), comprising:
The sealing system further comprises a mechanical seal (44) surrounding the bush (18);
The air chamber (28) is in fluid communication with the annular chamber (56) of the mechanical seal (44), the annular chamber (56) opening to the bush (18). Sealing system according to claim 1, characterized in that a control device (72) is provided which acts on either the compressed air regulating valve (75) on the compressed air source side or the valve arrangement (66) on the outlet line side. 3. The supply according to claim 2, wherein when a predetermined liquid or moisture content is reached, an activation signal is passed to the control device (72) to initiate the draining process, or a liquid measuring device (76) triggers an alarm signal. A sealing system, characterized in that it is disposed on the line side. 4. A control device according to claim 3, characterized in that a collection container (94) collects liquid discharged from the air chamber (28) and an activation signal to initiate a draining process when a maximum liquid level in the collection container (94) is reached. 72) or a fill level meter (96) which triggers an alarm signal is arranged on the discharge line side. Sealing system according to claim 4, characterized in that the throttle (70) is arranged on the side of the discharge line. Sealing system according to claim 5, characterized in that the lubricant chamber (30) is sealed on the side opposite the air chamber (28) with respect to the interior (10), and an internal pressure lower than the oil pressure is present. delete A method of sealing a shaft (2) located under water, the method comprising:
The lubricant chamber 30 open to the shaft 2 is filled with lubricating oil, the axially adjacent air chamber 28 open to the shaft 2 is filled with air, and the chambers 28 , 30 are (2) radially inwardly closed by a bush 18 disposed thereon, a seal ring 36 is disposed between the chambers 28, 30, said seal ring 36 comprising two chambers 28 , 30) are separated from each other,
the air chamber (28) is in fluid communication with the annular chamber (56) of the mechanical seal (44), the annular chamber (56) open to the bush (18);
Method according to claim 1, characterized in that the air pressure in the air chamber (28) is set higher than the oil pressure in the lubricant chamber (30). Method according to claim 8, characterized in that the air chamber (28) is drained intermittently. A vessel according to any one of the preceding claims, characterized in that it comprises a sealing system (1) for sealing at least one propeller shaft (2).

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